Joseph S. Clark Jr.

Joseph Sill Clark Jr. (21 October 1901-12 January 1990) was a US Senator from Pennsylvania (D) from 3 January 1957 to 3 January 1969, succeeding James H. Duff and preceding Richard Schweiker; he previously served as Mayor of Philadelphia from 7 January 1952 to 2 January 1956, succeeding Bernard Samuel and preceding Richardson Dilworth.

Biography
Joseph Sill Clark Jr. was born in Philadelphia, Pennsylvania in 1901, the son of a tennis player. After graduating from the University of Pennsylvania Law School, he pursued a law career in his hometown, and he became involved in the reform movement which challenged the city's powerful Republican political machine. He served in the US Air Force during World War II, and Clark was elected City Controller in 1949, investigating and publicizing scandals in the city's government. In 1951, he became the first Democrat to be elected Mayor of Philadelphia since 1884, and he reduced corruption and created low-income housing projects. After one term as mayor, he was elected to the US Senate in 1956, and he was a strong supporter of civil rights and appointed liberal committee members from the Democratic Steering Committee. His support of gun control and opposition to the Vietnam War cost him re-election in 1967, and he worked as a professor at Temple University before dying in 1990.